From dot at dotat.at Tue Apr 1 07:39:27 2008 From: dot at dotat.at (Tony Finch) Date: Tue, 1 Apr 2008 12:39:27 +0100 Subject: [LEAPSECS] operational time -- What's in a name? In-Reply-To: <23BA9A7D-01F5-4946-8F39-756B13F2EAD3@noao.edu> References: <0252D543-5185-45F8-98EB-F80907B51CE3@noao.edu> <874E8387-74D5-4EED-99C9-D5BB76FD2C30@noao.edu> <003e01c8935f$722ae890$9187db48@Fnord> <23BA9A7D-01F5-4946-8F39-756B13F2EAD3@noao.edu> Message-ID: On Mon, 31 Mar 2008, Rob Seaman wrote: > > Like I said, the clocks remained synced through several visits suggesting that > they received a signal on a regular schedule. They do turn the lights off at > night, I presume. The underlying clocks are undoubtedly crap, but likely > can't drift very far in a day. I do tend to donate first thing in the > morning. It seems that the reason my MSF clock didn't switch to DST was its position - moving it allowed it to resync correctly. (Possibly the problem was it faced west and the transmitter is north.) I didn't notice the lack of sync earlier because the clock has no sync indicator, and its quartz mechanism was accurate to within a second over three months. My quartz wristwatch is similarly accurate, even though it lacks temperature stability because I don't wear it all the time. Like you I expected them to be much worse, probably because of the bad reputation of quartz oscillators in computers. Tony. -- f.anthony.n.finch http://dotat.at/ DOVER WIGHT PORTLAND PLYMOUTH: SOUTHWEST VEERING WEST 5 TO 7, DECREASING 4 AT TIMES. MODERATE OR ROUGH, OCCASIONALLY VERY ROUGH IN PLYMOUTH. OCCASIONAL RAIN, FOG PATCHES. MODERATE OR GOOD, OCCASIONALLY VERY POOR. From dot at dotat.at Tue Apr 1 07:42:54 2008 From: dot at dotat.at (Tony Finch) Date: Tue, 1 Apr 2008 12:42:54 +0100 Subject: [LEAPSECS] operational time -- What's in a name? In-Reply-To: <20080331213632.GB62867@finch-staff-1.thus.net> References: <0252D543-5185-45F8-98EB-F80907B51CE3@noao.edu> <874E8387-74D5-4EED-99C9-D5BB76FD2C30@noao.edu> <20080331213632.GB62867@finch-staff-1.thus.net> Message-ID: On Mon, 31 Mar 2008, Clive D.W. Feather wrote: > > Um, what buttons on the back? My kitchen RC clock has none such (probably > because just about all of the UK is in the same time zone). Mine has buttons to request a radio sync and for manual setting. http://www.precisionclocks.co.uk/Instructions%20(PDF's)/PREC0002.pdf Tony. -- f.anthony.n.finch http://dotat.at/ SOUTHEAST ICELAND: NORTHEAST 7 TO SEVERE GALE 9 VEERING EAST 5 TO 7. VERY ROUGH OR HIGH . OCCASIONAL RAIN OR SLEET. MODERATE OR POOR. From phk at phk.freebsd.dk Tue Apr 1 10:15:51 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Tue, 01 Apr 2008 14:15:51 +0000 Subject: [LEAPSECS] operational time -- What's in a name? In-Reply-To: Your message of "Tue, 01 Apr 2008 12:39:27 +0100." Message-ID: <35420.1207059351@critter.freebsd.dk> In message , Tony Finch writes: >It seems that the reason my MSF clock didn't switch to DST was its >position - moving it allowed it to resync correctly. This is one of my major issues with radio-sync clocks: they seldom tell you they have no idea what time it really is. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From seaman at noao.edu Tue Apr 1 15:54:26 2008 From: seaman at noao.edu (Rob Seaman) Date: Tue, 1 Apr 2008 12:54:26 -0700 Subject: [LEAPSECS] Risks Digest DST articles Message-ID: <0EC63799-CA6B-47BE-9A5D-6AED60A91A04@noao.edu> LEAPSECS own Tony Finch has a couple of time related contributions in the current ACM Risks Digest, including a cartoon lampooning daylight saving time: http://catless.ncl.ac.uk/Risks/25.10.html#subj4 ...as well as a more serious DST proposal, quite worthy of our consideration: http://catless.ncl.ac.uk/Risks/25.10.html#subj1 Those interested might start by first reading a slightly more speculative contribution ("Australia & NZ should totally abandon Daylight Savings Time") from a different author: http://catless.ncl.ac.uk/Risks/25.10.html#subj5 Glad to see timekeeping issues receive the widespread attention they deserve. Rob From sla at ucolick.org Tue Apr 8 10:21:05 2008 From: sla at ucolick.org (Steve Allen) Date: Tue, 8 Apr 2008 07:21:05 -0700 Subject: [LEAPSECS] TI incunabula Message-ID: <20080408142105.GA22204@ucolick.org> Popular spreading of the notion of International Time for telecommunications, using that name, predates the 1884 International Meridian Conference. The New York Times reported on that in 1882. http://query.nytimes.com/mem/archive-free/pdf?_r=1&res=9F06E6DF123BE033A25754C1A9679C94639FD7CF&oref=slogin -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855 University of California Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m From seaman at noao.edu Tue Apr 8 11:44:51 2008 From: seaman at noao.edu (Rob Seaman) Date: Tue, 8 Apr 2008 08:44:51 -0700 Subject: [LEAPSECS] TI incunabula In-Reply-To: <20080408142105.GA22204@ucolick.org> References: <20080408142105.GA22204@ucolick.org> Message-ID: Steve Allen wrote: > Popular spreading of the notion of International Time for > telecommunications, using that name, predates the 1884 International > Meridian Conference. The New York Times reported on that in 1882. > > http://query.nytimes.com/mem/archive-free/pdf?_r=1&res=9F06E6DF123BE033A25754C1A9679C94639FD7CF&oref=slogin The most obvious thing about that newspaper article is how extremely well written it is. Forget about declining standards of timekeeping - the standards of journalism are atrocious today. My new pet project is to restore the U.S. Central timezone to the wonderfully poetic name of Mississippi Valley time. We should also start prepending the implicit "Rocky" in front of Mountain time. As a loyal, albeit prodigal, son of Philadelphia, I champion the proper recognition of Mr. Balboa. The name Atlantic time from the NYT article was ultimately assigned to a different zone, of course. One also wonders about the Eastern timezone of North America, which is the Western timezone of South America. Oh yeah! I also heartily support Steve's implicit message here. Rather than trashing one timescale, let's just simply complete the proper system engineering started in the Nineteenth century and call any such new timescale "International Time". Rob Seaman NOAO From phk at phk.freebsd.dk Tue Apr 8 11:47:08 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Tue, 08 Apr 2008 15:47:08 +0000 Subject: [LEAPSECS] TI incunabula In-Reply-To: Your message of "Tue, 08 Apr 2008 08:44:51 MST." Message-ID: <40270.1207669628@critter.freebsd.dk> In message , Rob Seaman writes: >Oh yeah! I also heartily support Steve's implicit message here. >Rather than trashing one timescale, let's just simply complete the >proper system engineering started in the Nineteenth century and call >any such new timescale "International Time". It has always seemed very pretentious to me, that a timescale bound tightly to a particular rotating rock was called "Universal". I can live with International Time as a name, but would far prefer to have it be Terrestial Time, so it names the rock in question. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From imp at bsdimp.com Tue Apr 8 12:02:24 2008 From: imp at bsdimp.com (M. Warner Losh) Date: Tue, 08 Apr 2008 10:02:24 -0600 (MDT) Subject: [LEAPSECS] TI incunabula In-Reply-To: <40270.1207669628@critter.freebsd.dk> References: <40270.1207669628@critter.freebsd.dk> Message-ID: <20080408.100224.-135503056.imp@bsdimp.com> In message: <40270.1207669628 at critter.freebsd.dk> "Poul-Henning Kamp" writes: : In message , Rob Seaman writes: : : >Oh yeah! I also heartily support Steve's implicit message here. : >Rather than trashing one timescale, let's just simply complete the : >proper system engineering started in the Nineteenth century and call : >any such new timescale "International Time". : : It has always seemed very pretentious to me, that a timescale bound : tightly to a particular rotating rock was called "Universal". Hmmm, tightly rotating rocks.... : I can live with International Time as a name, but would far prefer : to have it be Terrestial Time, so it names the rock in question. Or better yet, Earth Terrestial Time or Earth Normal Time or Commercial Time, since TT already is an abbreviation for some other timescale... Warner From seaman at noao.edu Tue Apr 8 12:52:04 2008 From: seaman at noao.edu (Rob Seaman) Date: Tue, 8 Apr 2008 09:52:04 -0700 Subject: [LEAPSECS] TI incunabula In-Reply-To: <20080408.100224.-135503056.imp@bsdimp.com> References: <40270.1207669628@critter.freebsd.dk> <20080408.100224.-135503056.imp@bsdimp.com> Message-ID: <9AFF2511-8B72-4A37-9F7B-494BDD4D5B59@noao.edu> M. Warner Losh wrote: > Poul-Henning Kamp writes: > >> I can live with International Time as a name, but would far prefer >> to have it be Terrestial Time, so it names the rock in question. > > Or better yet, Earth Terrestial Time or Earth Normal Time or > Commercial Time, since TT already is an abbreviation for some other > timescale... Um...TT is the abbreviation for "Terrestrial Time". It isn't the rock that places requirements on civil timekeeping, it is our internationally diverse civilization that derives requirements from the rock. For instance, the Mars rover project derives additional requirements from another rock. Rob From lang at unb.ca Wed Apr 9 08:07:44 2008 From: lang at unb.ca (Richard B. Langley) Date: Wed, 9 Apr 2008 09:07:44 -0300 (ADT) Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd) Message-ID: ---------- Forwarded message ---------- Date: Wed, 9 Apr 2008 07:50:40 +0200 From: central_bureau at iers.org To: messages at iers.org Subject: IERS Message No. 129: Plots of Earth Orientation Data ************************************************************************ IERS Message No. 129 April 09, 2008 ************************************************************************ Plots of Earth Orientation Data Some of the Earth Orientation Data provided by the IERS (see http://www.iers.org/MainDisp.csl?pid=36-9) can now be visualized by a simple click on the graphic symbols at this web page. The data include pole coordinates, UT1-UTC, LOD, and celestial pole offsets. The plots may be enlarged by clicking on them. Please be reminded also of the interactive tools for selecting, plotting, and analyzing time series of the Earth orientation available at the IERS Earth Orientation Centre ((http://hpiers.obspm.fr/eop-pc), which were announced in IERS Message No. 46. Bernd Richter and Wolfgang Schwegmann IERS Central Bureau ************************************************************************ IERS Messages are edited and distributed by the IERS Central Bureau. To subscribe or unsubscribe, please write to . Archives: http://www.iers.org/iers/publications/messages/ ************************************************************************ From seaman at noao.edu Wed Apr 9 09:37:21 2008 From: seaman at noao.edu (Rob Seaman) Date: Wed, 9 Apr 2008 06:37:21 -0700 Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd) In-Reply-To: References: Message-ID: <8865F2B0-CD8D-4BDE-B1A9-3EEA16063037@noao.edu> Yeah, I saw that too, but haven't figured out what symbols he's talking about. I just see the familiar text files. Anybody have specific links? Rob -- On Apr 9, 2008, at 5:07 AM, Richard B. Langley wrote: > ---------- Forwarded message ---------- > Date: Wed, 9 Apr 2008 07:50:40 +0200 > From: central_bureau at iers.org > To: messages at iers.org > Subject: IERS Message No. 129: Plots of Earth Orientation Data > > ************************************************************************ > IERS Message No. 129 April 09, > 2008 > ************************************************************************ > > > Plots of Earth Orientation Data > > Some of the Earth Orientation Data provided by the IERS (see > http://www.iers.org/MainDisp.csl?pid=36-9) can now be visualized by a > simple click on the graphic symbols at this web page. The data include > pole coordinates, UT1-UTC, LOD, and celestial pole offsets. The plots > may be enlarged by clicking on them. > > Please be reminded also of the interactive tools for selecting, > plotting, and analyzing time series of the Earth orientation available > at the IERS Earth Orientation Centre ((http://hpiers.obspm.fr/eop-pc), > which were announced in IERS Message No. 46. > > Bernd Richter and Wolfgang Schwegmann > IERS Central Bureau > > > ************************************************************************ > IERS Messages are edited and distributed by the IERS Central Bureau. > To subscribe or unsubscribe, please write to > . > Archives: http://www.iers.org/iers/publications/messages/ > ************************************************************************ > > _______________________________________________ > LEAPSECS mailing list > LEAPSECS at leapsecond.com > http://six.pairlist.net/mailman/listinfo/leapsecs From dot at dotat.at Wed Apr 9 09:50:44 2008 From: dot at dotat.at (Tony Finch) Date: Wed, 9 Apr 2008 14:50:44 +0100 Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd) In-Reply-To: <8865F2B0-CD8D-4BDE-B1A9-3EEA16063037@noao.edu> References: <8865F2B0-CD8D-4BDE-B1A9-3EEA16063037@noao.edu> Message-ID: On Wed, 9 Apr 2008, Rob Seaman wrote: > Yeah, I saw that too, but haven't figured out what symbols he's talking about. > I just see the familiar text files. Anybody have specific links? http://www.iers.org/MainDisp.csl?pid=36-1100218 The link is the small white square with the red diagonal line between "Finals.all (IAU1980)" and "version metadata". Tony. -- f.anthony.n.finch http://dotat.at/ LUNDY FASTNET IRISH SEA: WEST OR SOUTHWEST 3 OR 4, OCCASIONALLY 5 IN FASTNET LATER. SLIGHT, BUT MODERATE IN WEST FASTNET. SHOWERS. MAINLY GOOD. From phk at phk.freebsd.dk Wed Apr 9 09:53:31 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Wed, 09 Apr 2008 13:53:31 +0000 Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd) In-Reply-To: Your message of "Wed, 09 Apr 2008 14:50:44 +0100." Message-ID: <44959.1207749211@critter.freebsd.dk> In message , Tony Fi nch writes: >On Wed, 9 Apr 2008, Rob Seaman wrote: > >> Yeah, I saw that too, but haven't figured out what symbols he's talking about. >> I just see the familiar text files. Anybody have specific links? > >http://www.iers.org/MainDisp.csl?pid=36-1100218 And the interesting one of course is: http://www.iers.org/plots/FinalsAllIAU1980-UT1-UTC-BULA.png Should we make an informal bet on when the next leap second happens ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From seaman at noao.edu Wed Apr 9 11:45:52 2008 From: seaman at noao.edu (Rob Seaman) Date: Wed, 9 Apr 2008 08:45:52 -0700 Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd) In-Reply-To: <44959.1207749211@critter.freebsd.dk> References: <44959.1207749211@critter.freebsd.dk> Message-ID: <98D91D01-1536-4EF2-A6BA-467F5AC0270A@noao.edu> On Apr 9, 2008, at 6:53 AM, Poul-Henning Kamp wrote: > And the interesting one of course is: > > http://www.iers.org/plots/FinalsAllIAU1980-UT1-UTC-BULA.png This is an up to date version of the first figure (labeled figure 3) from my screed of exactly seven years ago today: http://iraf.noao.edu/~seaman/leap Remarkable how issues that aren't resolved keep coming back at you :-) How to optimize the scheduling algorithm for leap seconds has always been one of the more interesting - and potentially more productive - questions, whether it is your 10 year look ahead or the other extreme of permitting monthly leap seconds as I described. What clever chap was it who suggested ALWAYS having a leap second at the end of each month - toggling positive and negative? An actual leap transition then becomes the omission of a (negative) leap. Since systems would have to deal with the monthly cadence they would be forced to work correctly. (Evolution trumps design any day.) And since a leap would be the absence of an event, nothing would break. More to the point, all of these strategies are permitted under the current UTC standard :-) > Should we make an informal bet on when the next leap second happens ? I'll take December 2008. A Carlsberg Elephant (what do the locals drink?) versus your choice from the Nimbus brewery in Tucson? Rob --- http://nimbusbeer.qwestoffice.net/thebeers.html From phk at phk.freebsd.dk Wed Apr 9 11:52:43 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Wed, 09 Apr 2008 15:52:43 +0000 Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd) In-Reply-To: Your message of "Wed, 09 Apr 2008 08:45:52 MST." <98D91D01-1536-4EF2-A6BA-467F5AC0270A@noao.edu> Message-ID: <45825.1207756363@critter.freebsd.dk> In message <98D91D01-1536-4EF2-A6BA-467F5AC0270A at noao.edu>, Rob Seaman writes: >What clever chap was it who suggested ALWAYS having a leap second at >the end of each month - toggling positive and negative? An actual >leap transition then becomes the omission of a (negative) leap. Since >systems would have to deal with the monthly cadence they would be >forced to work correctly. (Evolution trumps design any day.) And >since a leap would be the absence of an event, nothing would break. Provided you get the funding sorted out, I'm all for it. Without funding, that proposal is deader than a doornail[1] >> Should we make an informal bet on when the next leap second happens ? > >I'll take December 2008. A Carlsberg Elephant (what do the locals >drink?) versus your choice from the Nimbus brewery in Tucson? That was my guess too... Elephants are falling out of fashion here, along with pretty much any other Carlsberg product. In the last couple of years Denmark has gone from 8 to several thousand (mostly micro-)breweries as a tasteful revolution against industrialized beer has taken hold. But I'll promise you a good beer if you pop around here, no matter what. Poul-Henning [1] For a quantification of this, see: http://www.amazon.com/Best-Annals-Improbable-Research/dp/0716730944 -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From seaman at noao.edu Wed Apr 9 12:43:47 2008 From: seaman at noao.edu (Rob Seaman) Date: Wed, 9 Apr 2008 09:43:47 -0700 Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd) In-Reply-To: <45825.1207756363@critter.freebsd.dk> References: <45825.1207756363@critter.freebsd.dk> Message-ID: <9EF73E8A-9777-436D-99F8-1EE5656F7B70@noao.edu> Poul-Henning Kamp wrote: > In message <98D91D01-1536-4EF2-A6BA-467F5AC0270A at noao.edu>, Rob > Seaman writes: > >> What clever chap was it who suggested ALWAYS having a leap second at >> the end of each month - toggling positive and negative? An actual >> leap transition then becomes the omission of a (negative) leap. >> Since >> systems would have to deal with the monthly cadence they would be >> forced to work correctly. (Evolution trumps design any day.) And >> since a leap would be the absence of an event, nothing would break. > > Provided you get the funding sorted out, I'm all for it. What funding? M. Gambis already has this authority as long as he stays within the +/- 0.9s window. Having reached a consensus among diverse parties and resolved the funding question, all in favor? :-) Like I said, all these scheduling variations are permitted under the UTC standard that is currently in effect. Your figure of merit is to maximize the look-ahead. Mine is to minimize excursions beyond 0.5s. Early UTC scheduling was clearly biased toward issuing a leap second as early as possible (permitting slack later). Recent UTC scheduling appears to be biased toward holding off on a leap second as long as possible (with the notion perhaps that each will be the last). > Elephants are falling out of fashion here, along with pretty much > any other Carlsberg product. In the last couple of years Denmark > has gone from 8 to several thousand (mostly micro-)breweries as a > tasteful revolution against industrialized beer has taken hold. This is the most hopeful sign for the future of our civilization that I've heard yet. > But I'll promise you a good beer if you pop around here, no matter > what. I may change planes in Munich on the way to Trieste in May. That's about as close as I'm likely to pop :-( You would think the home of Tycho would feature more prominently on the astronomical jet-set circuit. My father developed a taste for Tuborg when he was doing business in Copenhagen in the 60's, but I gather that's owned by Carlsberg now, too. > [1] For a quantification of this, see: > http://www.amazon.com/Best-Annals-Improbable-Research/dp/0716730944 I can also recommend: http://www.amazon.com/Being-Certain-Believing-Right-Youre/dp/0312359209 :-) Rob From phk at phk.freebsd.dk Wed Apr 9 13:02:58 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Wed, 09 Apr 2008 17:02:58 +0000 Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd) In-Reply-To: Your message of "Wed, 09 Apr 2008 09:43:47 MST." <9EF73E8A-9777-436D-99F8-1EE5656F7B70@noao.edu> Message-ID: <50661.1207760578@critter.freebsd.dk> In message <9EF73E8A-9777-436D-99F8-1EE5656F7B70 at noao.edu>, Rob Seaman writes: >> Provided you get the funding sorted out, I'm all for it. > >What funding? M. Gambis already has this authority as long as he >stays within the +/- 0.9s window. I could imagine that M. Gambis would run short of funds and possibly employment if he tried it. >> Elephants are falling out of fashion here, along with pretty much >> any other Carlsberg product. In the last couple of years Denmark >> has gone from 8 to several thousand (mostly micro-)breweries as a >> tasteful revolution against industrialized beer has taken hold. > >This is the most hopeful sign for the future of our civilization that >I've heard yet. Well, it's conflicting evidence: http://www.theinquirer.net/gb/inquirer/news/2008/04/08/climate-change-hits-beer -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From tvb at LeapSecond.com Thu Apr 10 02:44:30 2008 From: tvb at LeapSecond.com (Tom Van Baak) Date: Wed, 9 Apr 2008 23:44:30 -0700 Subject: [LEAPSECS] IERS Message No. 129: Plots of Earth OrientationData (fwd) References: <44959.1207749211@critter.freebsd.dk> Message-ID: <001101c89ad6$5767abf0$0a00a8c0@pc52> > Should we make an informal bet on when the next leap second happens ? http://www.leapsecond.com/java/nixie.htm /tvb From tvb at LeapSecond.com Thu Apr 10 15:49:31 2008 From: tvb at LeapSecond.com (Tom Van Baak) Date: Thu, 10 Apr 2008 12:49:31 -0700 Subject: [LEAPSECS] Electromagnetic Link Deep in the Earth Varies the Length of the Day Message-ID: <002001c89b44$0663bbe0$0a00a8c0@pc52> This may be of interest: Electromagnetic Link Deep in the Earth Varies the Length of the Day http://www.spectrum.ieee.org/print/6123 see also: The Electrical Conductivity of Post-Perovskite in Earth's D'' Layer http://www.sciencemag.org/cgi/content/full/320/5872/89 or: http://www.spectrum.ieee.org/apr08/6123 http://www.sciencemag.org/content/vol320/issue5872/index.dtl /tvb From lang at unb.ca Sat Apr 12 22:55:06 2008 From: lang at unb.ca (Richard B. Langley) Date: Sat, 12 Apr 2008 23:55:06 -0300 (ADT) Subject: [LEAPSECS] Book: One time fits all : the campaigns for global uniformity Message-ID: FYI. Bartky also wrote Selling the True Time: Nineteenth-Century Timekeeping in America (Stanford Univ. Press, Stanford, CA, 2000) and died last December. Obit here: Bartky, Ian R. One time fits all : the campaigns for global uniformity / Ian R. Bartky. Stanford, CA : Stanford University Press, 2007. xxv, 292 p. : ill., maps ; 24 cm. [Includes bibliographical references and index.] ISBN: 0-8047-5642-2 (Cloth/HB 49.95 USD) LC Class: QB223 Dewey: 389/.17 22 LC Subject Headings: Time--Systems and standards. "One Time Fits All" provides the first full framework for understanding attributes of civil time, which is used throughout the world today. It focuses on three components of uniform time all linked to the prime meridian at Greenwich - the International Date Line, the worldwide system of Standard Time zones, and Daylight Saving Time (Summer Time) - tracing the story of their beginnings and eventual acceptance from original sources in Europe, Great Britain, Canada, and the United States. The book concludes with an examination of the recent changes in America's Daylight Saving Time that took effect in 2007. =============================================================================== Richard B. Langley E-mail: lang at unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ =============================================================================== From Michael.Deckers at fujitsu-siemens.com Mon Apr 14 10:38:16 2008 From: Michael.Deckers at fujitsu-siemens.com (Deckers, Michael) Date: Mon, 14 Apr 2008 16:38:16 +0200 Subject: [LEAPSECS] TI incunabula Message-ID: <3958B14F314B884890EEE2F4CCDAB6A68C2E8B2AD2@ABGEX73E.FSC.NET> On 2008-04-08, Steve Allen posted an interesting NY Times article of 1882-01-17 on International Time. The article states that the Third International Geographical Congress (TIGC) of 1881-09 was held in Vienna. This is incorrect: that congress convened not in Vienna but in Venice (which arguably is nicer in September anyway). See for instance [Derek Howse: "Greenwich Time and the Longitude". pages 130..131 in the 1997 edition]. Michael Deckers From sla at ucolick.org Mon Apr 21 01:51:30 2008 From: sla at ucolick.org (Steve Allen) Date: Sun, 20 Apr 2008 22:51:30 -0700 Subject: [LEAPSECS] time for HRH Victoria Message-ID: <20080421055130.GA28072@ucolick.org> In the year 1900 E. WALTER MAUNDER, F.R.A.S produced a treasure of a work titled The ROYAL OBSERVATORY GREENWICH currently available online at http://atschool.eduweb.co.uk/bookman/library/ROG/INDEX.HTM In chapter VI is this quote There are few questions more frequently put than, 'What time is it?' 'Can you tell me the true time? 'A stickler for exactitude might reply, 'What kind of time do you mean?' 'Do you mean solar or sidereal time?' 'Apparent time or mean time?' 'Local time or standard time?' There are all these six kinds of time, but it is only within the last two generations, within, indeed, the reign of our Sovereign, Queen Victoria, that the subject of the differences of most of these kinds of time has become of pressing importance to any but theorists. Proliferation of time scales predates the atomic resonator. It's a thing that humans do. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855 University of California Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m From clive at demon.net Mon Apr 21 11:49:33 2008 From: clive at demon.net (Clive D.W. Feather) Date: Mon, 21 Apr 2008 16:49:33 +0100 Subject: [LEAPSECS] time for HRH Victoria In-Reply-To: <20080421055130.GA28072@ucolick.org> References: <20080421055130.GA28072@ucolick.org> Message-ID: <20080421154933.GG88574@finch-staff-1.thus.net> It's not "HRH Victoria", it's "HIM Queen-Emperor Victoria". She stopped being an HRH in 1837. -- Clive D.W. Feather | Work: | Tel: +44 20 8495 6138 Internet Expert | Home: | Fax: +44 870 051 9937 Demon Internet | WWW: http://www.davros.org | Mobile: +44 7973 377646 THUS plc | | From sla at ucolick.org Mon Apr 21 23:00:30 2008 From: sla at ucolick.org (Steve Allen) Date: Mon, 21 Apr 2008 20:00:30 -0700 Subject: [LEAPSECS] Delta T to 2 seconds over 50 years? Message-ID: <20080422030030.GA8384@ucolick.org> Online rumor that ObsPM may be prepared to assert predictions of Delta T, and thus leap seconds, to two seconds over an interval of 50 years. http://groups.google.com/group/NavList/browse_thread/thread/6b49f72f72fe84e3/21930961759798a2?hl=en#21930961759798a2 That might just alleviate the objections to putting the leap seconds into the zoneinfo database. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855 University of California Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m From phk at phk.freebsd.dk Tue Apr 22 02:10:53 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Tue, 22 Apr 2008 06:10:53 +0000 Subject: [LEAPSECS] Delta T to 2 seconds over 50 years? In-Reply-To: Your message of "Mon, 21 Apr 2008 20:00:30 MST." <20080422030030.GA8384@ucolick.org> Message-ID: <1531.1208844653@critter.freebsd.dk> In message <20080422030030.GA8384 at ucolick.org>, Steve Allen writes: >Online rumor that ObsPM may be prepared to assert predictions of Delta >T, and thus leap seconds, to two seconds over an interval of 50 years. That would certainly remove my primary objection to leap-seconds. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From sla at ucolick.org Mon Apr 28 21:58:07 2008 From: sla at ucolick.org (Steve Allen) Date: Mon, 28 Apr 2008 18:58:07 -0700 Subject: [LEAPSECS] move over Greenwich, Mecca calls Message-ID: <20080429015807.GA16120@ucolick.org> The blogosphere is abuzz about the conference in Qatar Mecca, the Centre of the Earth, Theory and Practice http://news.bbc.co.uk/1/hi/world/middle_east/7359258.stm http://en.wikipedia.org/wiki/Mecca_Time Disconnecting UTC from GMT, from the sun, may be playing with fire. The ITU-R is not constructed to handle these sorts of issues. This could be fun. I still think it's simplest if the ITU-R simply declares that time broadcasts would switch to a leapsecond-free, Torino-conference-like entity named such as TI, leaving UTC with BIPM. That would solve the ITU-R's problem -- getting a leap-free time scale. It makes everything else "someone else's problem", a strategy that is perfectly consistent with the historical actions of the CCIR and ITU-R. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855 University of California Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m